title: A qualitative gas chromatographic analysis of substituted 5,6-dihydroxyindoles from the urine of patients with melanoma.
abstract: A qualitative gas chromatographic analysis of trimethylsilylated ethyl acetate extracts of melanotic urine revealed 5 indolic compounds, which have been identified as substituted 5,6-dihydroxyindoles. Ethyl acetate extracts of melanotic urines at pH 2.0 contained isomeric 5-hydroxy-6-methoxy and 6-hydroxy-5-methoxy-indolyl-2-carboxylic acids which were not separable under the conditions used. A careful hydrolysis of melanotic urine with a Helix pomatia preparation followed by extraction at pH 6.5 in a nitrogen atmosphere released 3 additional indolic compounds from their conjugated form. Using gas chromatographic-mass spectrometric analysis they were identified as 5-hydroxy-6-methoxy, 6-hydroxy-5-methoxyindole and 5,6-dihydroxyindole.
mesh_terms: D002849:Chromatography, Gas; D004295:Dihydroxyphenylalanine / Q000652:urine*; D006801:Humans; D007211:Indoles / Q000652:urine*; D008543:Melanins / Q000096:biosynthesis; D008545:Melanoma / Q000652:urine*; D012878:Skin Neoplasms / Q000652:urine*
chemical_list: D007211:Indoles; D008543:Melanins; D004295:Dihydroxyphenylalanine